XPost: rec.radio.amateur.moderated
EI7GL....A diary of amateur radio activity
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Guest Post: VHF & UHF operation... by Alan Johnson, VK3DXE
Posted: 05 Dec 2021 12:00 AM PST
https://ei7gl.blogspot.com/2021/12/guest-post-vhf-uhf-operation-by-alan.html
VK3DXE in Australia recently posted this article on his Facebook page and
it is republished here with his kind permission to reach a wider audience.
In it, he outlines what attracted him to the VHF bands.
I've been a member of a number of VHF/UHF Ham pages for a while, and keep seeing a lot of misconceptions and myths being picked up and quoted over
and over by newcomers, and sadly a lot of not-so-newcomers who’ve brought their HF Game with them to the higher bands.
I first became fascinated with VHF tropo propagation as a young kid living
in the country, where we only had 2 TV channels, but occasionally we’d get the channels from the city suddenly appear when the conditions were right.
You can imagine the excitement for a young kid way back then who's suddenly discovered some new TV channels! We had a neighbour up the hill who
happened to be a Ham, and he explained to me how tropo worked. I was
hooked, and from then on, whenever the weather forecast maps looked
promising, and we got the right conditions, summer or winter, I’d start looking for the telltales that the city channels were going to pick up.
Fast forward 7 or 8 years, and I eventually got my Australian Novice
license, quickly upgrading to the Advanced Call within a year when I was
about 15 or 16. We were near the top of the sunspot cycle at the time, so I went nuts on HF for the next few years. But as the sunspots waned, I was
drawn to the higher bands…..
As a youngster it was sometimes tough putting up a decent 2m yagi, but I
always found a way of getting something in the air, and making the most of
what I had available, even when living in rental housing. I just had to be creative, and sometimes a bit cheeky. The good thing about a 2m yagi
though, was that even if anybody noticed it, they'd just figure it was a TV antenna..... You can build a small yagi like this in an afternoon with
some simple tools.
I learned about aircraft enhancement in the days before we had all the
funky tools we have today, before the widespread coming of the Internet. We managed to regularly make 2m SSB contacts of up to 700km (400+ miles) with smallish yagis and relatively low power - one path of 740km was quite good
even with my portable station, with just a little 4 element yagi and Yaesu FT-290R II running only 2.5 watts!
Living in inner city urban areas, I really began to appreciate low noise antenna designs (DL6WU & K1FO were the early leaders) and radio frontends
that didn't collapse in the presence of strong out of band signals. I
learned about GaAsFET LNAs (Low Noise Amplifiers, or preamps) too, and the importance of what was in front of the radio on RX. You have to think of
your station as a system.
In the early 1990’s the Bible of VHF+ was published. The VHF/UHF DX Book
very quickly became the must-have tome in every serious VHFer’s library. Although some of the chapters are now a bit dated, especially those
relating to equipment, I strongly suggest everybody with even a fleeting interest in the higher bands downloads a copy and reads it. Hopefully it’ll help to undo some of the myths about VHF+ that have persisted in the hobby
for far too long, things like the belief that troppo is only a summertime thing, and that troppo is the only worthwhile propagation mode on VHF+. Download it here:
http://www.trpub.net/assets/applets/VHF-UHF_DX_Book.pdf
As the Internet came along and people developed all sorts of new tools, and
we learnt about Forums, email reflectors, and then FaceBook pages, the opportunities to learn and collaborate grew amazingly.
Then the WSJT suite of software changed things overnight. All of a sudden,
the little guys running just 100w to a 10 element yagi could successfully
work stations on the other side of the world on 2m and above via EME, or Earth-Moon-Earth. I worked a dozen countries with just a single yagi and
less than 200w at the antenna.
Just last weekend, I was listening to HB9Q in Switzerland on 23cm for hours here in my /P shack while we're living in temporary accommodation, with a beautiful steady signal, often quite audible in the speaker, all on a tiny
60cm x 90cm gridpack antenna.
Eventually, once I get my 2.4m dish in the air and find a suitable
amplifier, I hope to be able to work him on 23cm SSB at home.... JT65 and
Q65 will be an absolute walk in the park.Lots of signals on 23cm with the gridpack.
In Australia, where we don’t have the population of Europe or North
America, the Ham fraternity have embraced WSPR on 2m, and have demonstrated
VHF paths of sometimes thousands of kilometres that no amount of listening
to white noise for beacons or a coincidentally-timed CQ would find with the naked ear. Those paths are now being exploited regularly on digital modes,
with people moving to SSB when conditions become strong enough. I've been around the hobby for a long time, but so too have the "old farts", some of
whom vociferously decry the use of digital modes, but our experience here
in Australia has really demonstrated how digital modes can be exploited to
help get those SSB contacts that very probably would never have taken place otherwise. WSPR has been so successful that there are now WSPR beacons on Hawaii (often heard on West Coast USA), and in New Zealand, with a
fantastic signal into East Coast Australia during the summer tropo season.A little 4 element Cushcraft yagi. Even this is enough to decode some of the
Big Guns off the Moon. I had many WSPR 2-ways with this one, out to 700km
with Aircraft Enhancement
Next time you're asked by anybody (PARTICULARLY CHILDREN AND YOUNG PEOPLE) about the hobby, instead of trying to excite them with boring stories of talking on HF or FM repeaters, which they tend to equate with the
equivalent of dialing random numbers on their cellphone to talk to old
farts with bad combover hairstyles about their hemorrhoids, try telling
them about stuff like all the space comms stuff we have access to, and can actively participate in, like using the repeater on the ISS, and all the
other satellites we have access to. Tell them about Moonbounce, and how you
can actually demonstrate the speed of light in action - you know exactly
when the station on the other end has stopped transmitting, but can still
see and hear his signal coming back at you for those additional 2 or 3
seconds it takes to travel all the way to the Moon and back. THAT gets
young people more excited than listening to old farts! Try talking to them about meteor scatter, and how the military has used it for communication systems to counter the effects of comms satellites being wiped out in a conflict, or a dirty big EMP bomb wiping out HF. Tell them about aircraft enhancement, which is really bistatic radar, and how some clever dude
worked out a way of using it to detect stealth aircraft by using commercial broadcasters behind enemy lines to illuminate the target. Tell them about
all the really funky atmospheric and weather science they can learn just by playing with weak signals on VHF+. Tell them about the funky networking knowledge they can gain from modes like D-Star, IRLP, Echolink, etc. The /P shack while I'm away from home
Anyways, I've written this piece in response to a recent influx of
newcomers and not-so-newcomers to the higher bands, possibly on the back of purchasing themselves a brand new IC-9700. I fully appreciate that
everybody starts their learning journey from different places and has
different interests, but some of the myths and misunderstandings I see are staggering. Unfortunately, so much of the Ham narrative has become very HF-centric, and that mindset often pervades discussions, and the marketing
of the hobby, so this is just my little bit to try to counter some of
that. Remember to download the VHF/UHF DX Book from the link above, and
jump onto some of the more technical pages and start learning.
I'll be doing a bit of a write up soon on the importance of frequency
accuracy and STABILITY on VHF+. Watch this space.
Enjoy!
de VK3DXE
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Successful WSPR reports on the 40 MHz band in the USA - Nov 2021
Posted: 03 Dec 2021 12:01 PM PST
https://ei7gl.blogspot.com/2021/12/successful-wspr-reports-on-40-mhz-band.html
Over the last few months seven stations in the USA have received
experimental permits for the 40 MHz band... see previous post.
While a few have tried FT8, a number have been using the WSPR mode as an experimental beacon.
A list of of some of the reports are shown below with maps shown above.
1) WX2XCC in California is operated by Chris, N3IZN and he has a remote receiver listening for his own WSPR transmissions. During what was probably
a Sporadic-E opening on the 40 MHz band, he was decoded by VA7MM in
Vancouver in western Canada at a distance of 1819 kms.
UTC (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km
2021-10-28 22:12 WM2XCC DM13 N3IZN/SDR DM13ji 40.663484 2 7 0 21
2021-11-28 17:48 WM2XCC DM13 VA7MM CN89og 40.663488 2 -17 0 1819
2) WM2XEJ in Georgia is operated by Tom, WB4JWM and his WSPR signal has
been reported by two stations... NZ2X and N4WLO.
UTC (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km
2021-11-23 15:08 WM2XEJ EM83 NZ2X EM83ij 40.663473 10 5 0 25
2021-11-29 17:48 WM2XEJ EM83 N4WLO EM50uo 40.663433 10 -23 0 589
While NZ2X is a local station, the distance to N4WLO is 589 kms which is
pretty short if it was Sporadic-E.
3) WX2XCW is operated by Hal, NR7V is just in the far north-west of
Washington state. He is very close to the city of Vancouver and all of the reports are from local Canadian stations.
UTC (y-m-d) TX txGrid RX rxGrid MHz W SNR drift 2021-10-28 22:06 WM2XCW CN88 VA7MM CN89og 40.663527 0.2 2 0
2021-10-28 22:06 WM2XCW CN88 VE7UTS CN89li 40.663524 0.2 -8 0
2021-11-22 18:16 WM2XCW CN88 VE7RPX CN89lh 40.663529 2 -16 0
2021-11-22 18:36 WM2XCW CN88 VE7AFZ CN89ji 40.663527 2 -28 0
Overall, it's still early days but hopefully more stations will start transmitting on WSPR and more will start listening and uploading their
spots to the WSPRnet website.
Link...1) More info on my 40 MHz page
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